This circuit was found in a Motorola documentation from 1975. Modern equivalent transistors such as the BF245 can be used. The circuit is powered by 9 V voltage from cells or batteries.
This busy line indicator is very simple, serving for analog lines. The supply is made by two...
This circuit was found in an 80's Electronic Engineering. The circuit uses operatives of the time...
Other operational amplifiers series, such as the MC34072, MC34074, MC35071, MC35072, MC35074 d...